The present invention relates to a container made out of a flat material like paper, cardboard, etc. with a ridged-seam closure, and especially to a parallelepipedal container for liquid and made out of paper, plastic, or composite.
Containers of this type, especially parallelepipedal containers for liquids are manufactured from both blanks and webs and shaped so that an opening can be cut with scissors in the vicinity of the sealed seam on the top to form a pouring spout. A container of this type with an upper folded section incorporating outside triangular folds is known from German Patent No. 1 298 929 for example. The problem of opening containers of this type has not yet been satisfactorily solved. The container described in the aforesaid patent has a perforated line in the vicinity of the triangular folds to facilitate opening. The composite commonly employed in aseptic containers, however, may consist not only of aluminum foil but also of tough plastic, and tearing a line perforated in this type of material is so difficult that a lot of strength must be employed to rip part of the seam along the perforations. Although it is of course possible in principle to make the perforations deeper in order to facilitate tearing, this is impossible with aseptic containers because the possibility of impairing tightness is not inconsiderable.